[Observium] add specific OID to a host to monitor.graph

Hi,

I'm working towards building some additional OS and device definitions for Observium.

At first, I would like to know if there is a way to add a specific OID to a device to be monitored. Other words, I have a device and the standard mibs are being monitored / graph'd. I'd like to add a specific OID to also be monitored / graphed.

thanks